[GRASSLIST:829] Re: Snapping across multiple vectors?

[Hamish]

> I checked on the list archives and the last time this question was
> asked was 2004, so I was wondering if snapping between two separate
> vectors has been implemented? I have a series of DGPS navigation fixes
> that I want to snap onto a ship trackline. Right now, the points are
> just a tad  offset from the lines (< 1m) and I want to make them
> topologically coincident.

You can't give line nodes or vertices attributes, only change them to
points and then give those points attributes. You can only give a line
as a whole an attribute.

v.to.points [-v]
v.distance upload=to_attr,dist  # works on nearest, up to "dmax"

(probably good to use v.distance upload=dist in a column then run
v.univar on result to check for any bad matches)


see example 6 on the v.distance help page:  (using spearfish dataset)
 http://grass.ibiblio.org/grass61/manuals/html61_user/v.distance.html



Hamish